366 THE OCEAN WORLD. 
a grain of sand even, round which has been deposited in concentric 
layers the beautiful and much-prized gem. : 
The Chinese, and other Fastern nations, are said to turn this fact 
in the natural history of this bivalve to practical use in making pearls 
and cameos. By introducing into the mantle of the mollusc, or into 
the interior of its body, a round grain of: sand, glass, or metal, they 
induce a deposit which in time yields a pearl, in the one case free, 
and in the other adhering to the shell. In some cases pearls are said 
to be produced in whole chaplets by the insertion of grains of quartz 
connected by a string into the mantle of a species of Meleagrina ; in 
other cases, a dozen enamelled figures of Buddha seated have been 
produced by inserting small plates of embossed metal in the valves of 
the same species. 
The pearls are very small at first ; they increase by annual layers 
deposited on the original nucleus, their brilliancy and shade of colour 
varying with that of the nacre from which they are produced. Some- 
times they are diaphanous, silky, lustrous, and more or less iridescent ; 
occasionally they turn out dull, obscure, and even smoky. 
The pearl oyster is met with in very different latitudes ; they are 
found in the Persian Gulf, on the Arabian coast, and in Japan, in the 
American seas, and on the shores of California, and in the islands of 
the South Sea ; but the most important fisheries are found in the Bay 
of Bengal, Ceylon, and other parts of the Indian Ocean. The Ceylon 
fisheries are under Government inspection, and each year, before the 
fisheries commence, an official inspection of the coast takes place. 
Sometimes the fishing is undertaken on account of the State, at 
other times it is let to parties of speculators. In 1804 the pearl 
fishery was granted to a capitalist for £120,000; but, to avoid im- 
poverishing all the beds at once, the same part of the gulf is not 
fished every year. 
The great fishery for mother-of-pearl Pintadines (A/¢/eagrina mar- 
garitifera) takes place in the Gulf of Manaar, a large bay to the north- 
east of the island : it commences in the month of February or March, 
and continues thirty days, taken collectively, and occupies 250 boats, 
which come from different parts of the coast ; they reach the ground 
at daybreak, the time being indicated by a signal gun. Each boat’s 
crew consists of twenty hands, and a negro, The rowers are ten in 
number. The divers divide themselves into two groups of five men 
each, who labour and rest alternately ; they descend from forty to 
fifty feet, seventy being the very utmost they can accomplish, and 
eighty seconds the longest period the best divers can remain under 
